Researchers track single-breath exhaled hydrogen cyanide patterns in real time.

A common gas that is toxic and dangerous is hydrogen cyanide (HCN), which has a high adsorption rate and high volatility. Hints of HCN are likewise tracked down in human breath. Surprisingly high HCN fixation in the breath of cystic fibrosis (CF) patients is related to Pseudomonas aeruginosa (Dad) contamination. As a result, rapid screening for PA infection in CF patients can be made possible by the development of an extremely sensitive online measurement of HCN in exhaled breath.

As of late, an exploration bunch driven by Prof. Li Haiyang from the Dalian Establishment of Synthetic Physical Science (DICP) of the Chinese Foundation of Sciences (CAS) has fostered a stream-aided photoionization mass spectrometry strategy for profiling hydrogen cyanide in breathed-out breath.

On April 4, the study was published in Analytical Chemistry.

“HCN is effectively dissolvable in water and exceptionally adsorbed on gadget surfaces, so awareness and reaction speed are principal challenges for straightforwardly estimating HCN in breathed-out breath at high stickiness,” said Prof. Chen Ping, co-creator of this review.

“Because HCN is easily soluble in water and highly adsorbed on device surfaces, sensitivity and response speed are the primary challenges that directly measuring HCN in exhaled breath at high humidity presents.”

Prof. Chen Ping, co-corresponding author of this study.

Improved sensitivity and time resolution of direct HCN measurements in exhaled breath were achieved by employing a self-developed atmospheric pressure negative photoionization time-of-flight mass spectrometer method developed by the researchers. This technique allowed for real-time monitoring of HCN concentrations in a single exhaled breath, which may make it possible to quickly screen CF patients for PA infection.

They suggested employing a shield gas made of helium within the mass spectrometry ionization source. The sensitivity of HCN detection was improved, ion transport efficiency was increased, and the effect of high humidity on ionization was lessened thanks to this strategy.

In addition, they enhanced the sampling system by shortening the sampling line and incorporating a gas purging procedure to effectively reduce HCN adsorption residue and enhance time resolution. With a resolution time of 0.5 s and a limit of detection of 0.3 ppbv, the researchers were able to monitor the changes in the single exhaled HCN profiles of volunteers before and after gargling. The subsequent profiles plainly showed an early pinnacle and a steady end-flowing level, addressing the grouping of the oral hole and end-flowing gas separately.

“In terms of HCN quantification, the new method demonstrated high accuracy and good interference resistance.” “It has likely applications in the discovery of Dad disease in CF patients,” said Prof. Li.

More information: Yuxuan Wen et al, Online Detection of HCN in Humid Exhaled Air by Gas Flow-Assisted Negative Photoionization Mass Spectrometry, Analytical Chemistry (2023). DOI: 10.1021/acs.analchem.2c05603

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